Bug: External program links won't open Vivaldi

For the past month, I've been using Vivaldi and the one thing I can't get it to do is open a link in vivaldi from another program. If I set Vivaldi as the default program, I'm totally unable to open http/https links, whether it's from an im chat or windows update or outlook. Sometimes I'll get the error message "class not registered" in certain programs. The only suggestion I've seen is to not have Vivaldi in program files or installed as all users, which is already the case for me. I always use the latest snapshot, currently on windows 8.1.